Many machines have been used in the past for spreading gravel along road surfaces and others have been used for placing asphalt. Current practices in road shouldering operations require the use of several machines to place the material to construction specifications. Machines used for placing asphalt are not easily mobilized and require the use of other machines for hauling or altering the slope of the material to satisfy construction specifications.
In the prior art, applicant is aware of U.S. Pat. No. 4,188,152 which issued to Kitt on Feb. 12, 1980 for a Gravel Spreader. Kitt teaches an apparatus for spreading, loose material, such as gravel, on a surface. The apparatus comprises an elongate material spreader for positioning generally parallel to the surface a distance above the surface. A frame extends forwardly and above the spreader to a pivotal connector for connecting the apparatus to a hopper trailer between the trailer and the surface. A first material retainer extends forwardly from the front of the spreader near one end of the spreader. A second material retainer extends forwardly from the front of the spreader. The first retainer is positionable a distance from the second retainer so that, when the material is distributed from the trailer a distance from the front of the spreader in a forward direction, the material is spread between the first and second retainers and between the bottom edge of the spreader and the surface, as the trailer moves in the forward direction along the surface.
The disadvantage of the Kitt device is that it must be followed by a road grader to place the material at an angle to the road surface. Consequently, there is little benefit to using the Kitt device over a conventional bottom dump trailer. The present invention on the other hand can place a desirable width of spreadable material at an angle inclined relative to the road surface. The Kitt device places material on the ground along the side of the device approximately 8 feet ahead of a spreader blade. The present invention places material directly into, or immediately ahead of, a blade cavity. This makes efficient use of the material in that material is not wasted. The placing of material into, or immediately ahead of, the blade cavity makes possible the accurate placing of material as the trailer is manoeuvred around sharp corners on the roadway. The present invention also allows the material to be placed over a roadside curb by means of a laterally extendable conveyor. The conveyor of the Kitt device is fixed relative to the trailer. The Kitt device can spread material from the edge of the trailer outward in one direction only. The present invention can spread material on either side of the trailer or under the trailer. In one embodiment, the blade in the present invention is located to the front of the trailer which allows for better visibility for the operator and better weight distribution when hauling material. The blade on the Kitt device cannot be seen at all by the operator when the trailer is making a left turn.
Applicant is also aware of U.S. Pat. No. 3,680,451 which issued to Birtchet on Aug. 1, 1972 for a Roadway Sloping Attachment for Asphalt paving Machine. Birtchet teaches an attachment for an asphalt paving machine which permits the machine to slope the outer edge of a roadway to a desired angle. A material spreading assembly is disclosed which includes a pivoted blade having means for adjusting the angle of the lower surface of the blade relative to the bottom line of the strike-off board. The pivoted blade portion is located between the end gate and the main blade (or board) so that the assembly when attached to a paving machine serves to lay down an angled shoulder to the roadway as a part of the continuous surface laying operation.
Applicant is also aware of U.S. Pat. No. 5,304,013 which issued to Parsons on Apr. 19, 1994 for a Road Shouldering Compacting Apparatus. Parsons discloses an offset compactor for use on a grader as the grader travels along the road. An adjustable connection is provided between the grader and the ground engagement member permitting displacement of the member laterally from either side of the grader allowing use of the ground engagement member on opposite sides of the grader. The ground engagement member is selectively adjustable so as to be selectively raised or lowered. The ground engagement member which, as taught by Parsons, is a pair of wheels, which are swung on an arm about a centrally located pivot so that the position of the wheels when swung out to either side of the grader are fixed. It is neither taught nor suggested to use the compacting wheels as load bearing wheels during transportation, nor to selectively adjustably extend the wheels laterally outwardly of the vehicle as taught in the present invention.